Leah takes a look at an astronaut nappy
15 December 2015 Last updated at 11:14 GMT
Astronaut Tim Peake has blasted off into space to become the first British man ever to board the International Space Station.
He's due to spend more than six months on board the ISS carrying out science experiments, completing a marathon and getting young people excited about space travel.
So, Leah has been chatting to astronaut Chris Hadfield about wearing a spacesuit and how you go to the loo during the six hour journey...